Single pivot x-ray table



Dec. 13, 1955 p, THOMAS r 2,726,910

SINGLE PIVOT X-RAY TABLE Filed Nov. 25, 1954 2 Sheets-Sheet 1 Fig.2.

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Q) 3 O 200 LL 0 45 90 Table Angle WITNESSES: |NVENTORS 4f EugeneP.Thomos 47! and Robert J.Wogner.

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' ATTORNEY Dec. 13, 1955 E. P. THOMAS ET AL SINGLE PIVOT X-RAY TABLE 2Sheets-Sheet 2 Filed NOV. 25, 1954 Fig.3.

United States Patent SINGLE PIVOT X-RAY TABLE Eugene P. Thomas andRobert J. Wagner, Baltimore, Md., assignors to Westinghouse ElectricCorporation, East Pittsburgh, Pa., a corporation of PennsylvaniaApplication November 23, 1954, Serial No. 476,774

Claims. (Cl. 311-6) The present invention relates to X-ray apparatus andrelates, in particular, to an X-ray table which is movable about asingle support pivot.

It is an object of the present invention to provide an improved X-raytable which is tiltable about a single support pivot.

It is an additional object of the present invention to provide animproved cantilever supported single pivot X-ray table having moresimple and less expensive control and drive apparatus for tilting orangulating the table relative to the table base or support floor.

It is a further object of the invention to provide a more reliable andimproved control apparatus for the tilting movement of an X-ray tableand for improving the table load characteristics.

It is another object of the present invention to provide an improvedcontrol for a single pivot X-ray table which provides a compensation forthe variation in table load characteristics as the table is tiltedbetween the opposite extremes of its allowable angular movement.

Other objects of this invention will be apparent upon reading thefollowing description taken in connection with the drawings, in which:

Figure l is a perspective view of the X-ray table apparatus inaccordance with the present invention;

Fig. 2 is a curve showing the compensating torque force applied by thespring control member to affect the tilt movement of the X-ray table;

Fig. 3 is a top plan view of the apparatus shown in Fig. 1, and

Fig. 4 is an end view of the apparatus shown in Fig. 1.

In general, we have provided a single pivot cantilever supported X-raytable which is controlled by a drive motor that applies its controlforce through a band brake controlled flywheel and drive sprocket to acontrol chain member which is operative with the contour surface of acam or control member fastened to the X-ray table. To further supportthe X-ray table in its cantilever position about the single supportpivot, a reaction roller or like device is provided to apply acompensating force to the X-ray table to counteract the gravitationalweight of the cantilever supported X-ray table. In addition, a springcontrol member is provided to compensate for the shifting effect of theX-ray table load due to the center of gravity of the X-ray table passingfrom one side to the other of the support pivot. The spring controlmember is operative to apply a compensating torque force such that theload characteristic of the X-ray table never reverses, and the movementof the X-ray table is, therefore, substantially smooth and continuous.

Referring to Fig. l and Figs. 3 and 4 of the drawings in detail, anX-ray table is cantilever supported about a pivot connection 12. Acontrol member 14 is rigidly fastened to the X-ray table 10 and isprovided with a contour surface having a predetermined shape about whichn a control chain member 16 is positioned and is operative.

F ice nection 20. A support base 22 is provided for the X-ray table 10such that the pivot connection 12 is fixedly supported by the supportbase 22, and the X-ray table 10 is movable or tiltable about the pivotconnection 12 relative to the support base 22. A drive motor 24 isprovided for effecting the tilt motion of the X-ray table 10 through thecontrol chain 16. The drive motor 24 is connected through a flywheel 26about which is operative a suitable hand brake 28. The drive motor 24 isalso connected to the drive sprocket 30 which is provided with suitableteeth such that it is operative to exert a force on the chain member 16when raising the table to pull on the connection 18 between the chain 16and the control member 14. When the motor 24 is reversed, the table 10is lowered by means of the sprocket 30 rotating to feed out the chain16. A stripper gear or like device 32 is provided to prevent fouling ofthe chain 16 even if the unloaded end of the chain becomes slack and hassubstantially no tension in it. The contour of the cam or control member14 is predetermined as shown in Fig. l to provide a maximum torque withminimum tilt speed of the X-ray table when the load is high, such aswhen the table is in a substantially horizontal position or when theX-ray table 10 is substantially parallel relative to the plane surfaceor bottom 25 of the support base 22, and further, to provide a minimumtorque with a maximum X-ray table tilt speed when the table load issmall, such as when the X-ray table 10 is in an angular position ofapproximately 60 degrees or more relative to the bottom or plane surface25 of the support base 22. The contour surface of the cam or controlmember 14 is operative such that it is effective to take up the chain 16from the sprocket 30 at approximately the same rate as the chain 16 ispulled into the sprocket 30 when the motor 24 is rotating in eitherdirection. The illustrated contour surface of the cam or control member14 is superior to a circular arc shape in that a circular arc shape doesnot permit the desired adjustment of the table tilt speed or tiltingtorque to meet the table load characteristics.

The band brake 28 is operative with the flywheel 26 to provide asmoother stopping and starting of the table tilt movement. In startingto tilt the X-ray table 10, the flywheel 26 resists momentarily theapplied torque from the motor 24, and in stopping the tilt movement ofthe X-ray table 10 by means of the band brake 28, the flywheel isefiective to temporarily resist the action of the braking force. Theband brake 28 is operative for either rotational direction of the motor.

A spring control member 34 is provided to apply a compensating torque tomore desirably adjust the load characteristic of the X-ray table 10. Thespring control member 34 is fastened at one end 36 to the support base22, and the other end 38 is connected to a terminating plug or piston 40of a rope or cable 42. The cable 42 passes coaxially through the springcontrol member 34 and around a plurality of pulleys 44, 46, 48 and 50and is fastened to the cam or control member 14 by means of a pin orfastening member 52. The spring control member 34 is thereby held incompression by means of the cable 42 connected between the plug 40 andthe fastener 52 such that the spring control member 34 applies a forceto the cam or control member 14 to efiect the pivotal movement of theX-ray table 10 about the pivot connection 12, in accordance with thecurve shown in Fig. 2. The center of gravity of an actual X-ray table 10in accordance with the present invention is so located such that atapproximately 70 degrees angulation of the X-ray table 10 relative tothe bottom 25 of the support base 22, the load characteristic of theX-ray table shifts. In other Words, when the X-ray table 10 is atapproximately an angle of 70 degrees relative to the bottom Plate25. ofthe supnn bas t X- av a e t nds torque to the X-ray table through thefastener 52, which compensating torque starts to increase from a tableposition of approximately 45 degrees relative to the bottom plate. 24and increases as the table tilts to the vertical or approximately 90degree angular position relative to the bottom plate 25. Therefore, dueto the force applied by the spring control member 34, the X-ray tableload effectively never reverses in that the force of the control 7spring 34 overcomes the falling or gravitational effect of the X-raytable between the 70 degree angular position and the 90 degree angularposition. This results in the tilting movement of the X-ray table beingmade'very smooth and very *readily controllable by the motor 24 drivingthrough the drive sprocket and the chain control member 16. At a tabletilt position of approximately degrees relative to the bottom plate 25,the compression of the spring control member 34 is at a minimum. Fortable tilt positions from approximately 45 degrees to approximately 90degrees, the spring control member 34 is compressed in accordance withthe portion of the curve to the right of the 45 table angle, as shown inFig. 2. For a table tilt position from approximately 45 degrees down tozero and beyond in the Trendelenburg position up to 10 degrees, thespring control member 34 is used to store energy which is effective toraise the X-ray table lli back to approximately the 45 degree angularposition.

A reaction roller member 54 is provided and is rigidly fastened to thesupport base 22 and applies a counteracting force to the back ,orreverse side 'of the cam or control member 14 as shown inFig. l. Thereaction roller 54 is adjustable and is operative to ofliset the torqueresulting from the weight of the cantilever supported X-ray table 10.The reaction roller 54 is very desirable v in that without it thebearings at the pivot connection 12 must be strong enough to bythemselves completely resist the cantilever suspension torque.

The apparatus as shown in Fig. '1' and Figs. 3 and 4 providesgreaterrigidity and static stability in all positions. Bolts may beprovided to fasten the bottom plate 25 to a support floor or the like.However, this is not necessary in that the X-ray table apparatus willnot tip over in any desired tilt position of the X-ray table 10.Further, the reaction roller 54 not only reduces the torque load on thebearings at the pivot connection 12, but in addition, absorbs a largeportion of the X-ray table moment which would otherwise cause undesireddeflection and twisting'ofthe X-ray table. 7

In accordance with the operation of the apparatus shown in Fig. 1 andFigs. 3 and 4, the drive motor 24 descent of the table is governed bycontrolling the feed out or slackening of the chain 16 relative to theconnection 18. With a clockwise rotational direction of the "motor 24,theX-ray table can be tilted up to substantially a 90 degree positionrelative to the bottom plate 25.

With a counterclockwise rotation ofthe drive motor 24,

' the X-ray table can be tilted to the Trendelenburg position whichcorresponds to a position of the X-ray table which is 10 degrees belowthe horizontal position or parallel position relative to the bottomplate 25.

Although a specif c embodiment of the present invention'has been shownand described, it is to be underst od that st ll ur her modifisationsther o mayb made without departing from the spirit and scope of theinvention.

We claim as our invention:

1. In X-ray apparatus including a table tiltable about a pivot andhaving'asupport base, the combination of a control cam member fastenedto said table and including a predetermined contour surface having apair of end portions, control chain means fastened between said endportions and operative with said contour surface, and motor meansfastened to said support base and opera tive with said control chainmeans to tilt said table. about said pivot.

2. in X-ray apparatus including a table movable about a pivot and havinga support base with said support base having a plane surface, thecombination of a control member fastened to said table and having apredetermined contour surface, control means operative with saidsurface, motor meansoperative with said control means to control themovement of said table about said pivot with said contour surface beingshaped to provide a maximum torque for tilting the table when said'tableis positioned substantially parallel to said base and to .face, controlchain means fastened to said control cam member and operative with saidcontour surface, and motor means fastened to said support base andoperative with said control chain means to tilt said table about saidpivot, and a spring control member fastened to said table and operativeto apply a force to tilt said table about said pivot such that the tableload characterist c does not reverse as the table is tilted from saidfirst posit on to said second position.

4. ln X-ray apparatus including a table movable about a pivot, saidtable being cantilever supported about said pivot, the combination offirst control means fastened to said table and including a cam memberhaving a predetermined contour surface, second control means including acontinuous flexible member operative with said surface to control themovement of said table about said pivot and third control meansoperative with the cam member of said first control means to compensatefor the torque resulting from the cantilever support of said table.

5. in X-ray apparatus including a table tiltable about a pivot andhaving a support base, the combination of a control cam member fastenedto said table and including a predetermined contour surface having apair of end portions, control chain means fastened between said endportions and operative with said contour surface, and motor meansincluding a flywheel and drive sprocket, said motor means being fastenedto said support base and said drive sprocket being operative with saidcontrol chain means to tilt said table about said pivot, with said motormeans further including a band brake which is operative with saidflywheel to control the movement of said table.

Refereneest'lited the file of this patent UNITED STATES PATENTSi,820,436 Carlson Aug. 25, 3931 2,172,94l Manning et al Sept. 12, 19392,534,623 Pitts Dec. 19,1950 2,679,442 Koerner et al May 25, 19542,680,046 Stava June 1, r 2,692,173 'Lowitzsch Oct. 19, 1954 2,699,3671955 Lipphaus et a1. Jan. 11,

